Quick and dirty "load balancing" is round robin DNS. I just did a quick
test the other day and set up two machines with our app. Hit the URL
once and logged in (keeps object in session). Killed the app on one
machine and hit reload. I was still logged in on the other machine. I
got some errors as Netscape didn't choose to look at the other IP (in RR
DNS you specify multiple IPs for a single domain name) right off. But it
did show that session failover worked.
--
Joel Shellman
Chief Software Architect
The virally-driven B2B marketplace for outsourcing projects
http://www.ants.com/90589781
Kevin Duffey wrote:
>
> I have clustered Orion, but there is alot I don't know about it. I have
> learned that Orion does session replication to every server in the cluster
> farm. I have not been able to test it with a load-balancer yet. Anyone
> happen to know of a "free" software load-balancer that can be used to test
> multiple servers with?
>
> Clustering with Orion is easy. You just add a <cluster id="x" /> to
> server.xml on each server in the Orion/config dir. x is equal to a unique
> number on each server.
>
> then you add a <cluster-config /> to each orion-web.xml in the WEB-INF dir
> of a web app. That should cluster it.
>
> There are a number of issues I am not sure of however. If you run orion with
> the -console2 option, it brings up a SWING based admin console, and you can
> open the http tree and see the web-apps running, then look at sessions in
> each of those apps. When I cluster two servers, and hit one, the session
> data appears in both servers. However, on the server that the session was
> not created on, the values of the objects in the session are not available.
> This confuses me because I figured if I hit the other server that has been
> replicated to, and passed along the session ID (jsessionid=xxx), that it
> would automatically make that session available to me. However, one of our
> engineers mentioned that a session is stored via the ip address being hit.
> Thus, even though the session data is saved on two servers, trying to access
> the same session from two different ip addresses won't work. My only dilema
> here is..if a server goes down (say the one the session data was created
> on), so only one is left, does that automatically take over? I can't get
> this to work because I don't have a load balancer. I assume using a
> load-balancer is easy enough and this would work. Anyone from the Orion team
> care to respond..that would be great if you could explain how this is done.
